The DNA repair protein O6-Methylguanine-DNA methyltransferase (MGMT) is suggested to be associated with resistance to alkylating agents such as Temozolomide which is being used in treatment of patients with glioblastoma (GBM). Therefore, we evaluated the associations between MGMT promoter methylation and prognosis of patients with glioblastoma (GBM).Data were extracted from publications in Embase, PubMed, and the Cochrane Library. Data on overall survival (OS), progression-free survival (PFS), and MGMT methylation status were obtained and 4,097 subjects were enrolled. Data from 34 studies showed that MGMT methylated patients had better OS, compared to GBM unmethylated patients (pooled HRs,

Breast cancer is the second most common malignancy diagnosed in women, supporting the need for identification of novel prognostic and diagnostic biomarkers. Recently, microRNAs have emerged as molecular regulators that can have key roles in pathogenesis and progression of different malignancies, including breast cancer. Micro-RNAs can be circulated in body fluid, suggesting their values as non-invasive marker. There is growing body of evidence showing the aberrant activation of some known circulating miRNAs, for example let-151a, miR-21, miR-155, miR-,145 miR-18a, miR-16 as well as tissue specific-miRNAs, for example miR-182, miR-145, miR-21, miR-155/154, miR-203, miR-213, miR-7 in patients affected by breast cancer. In addition, there is growing body of evidences on the value of miRNAs to be associated with drug-resistance, suggesting their values as a potential approach to overcome chemo-resistance. Attuned with these facts, this review highlights recent preclinical and clinical investigation performed on tissue-specific miRNAs and circulating as novel promising biomarkers for detection of patients at early stages, prediction of prognosis, and monitoring of the patients in response to therapy.

This study has received fi nancial support from the research vice chancellor of the Mashhad University of Medical Sciences. Abstract BACKGROUND:Bone scan is a sensitive but not specific method for evaluation of bone metastases. However, the clinical

The V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) is frequently dysregulated in colorectal cancer (CRC). It is involved in the modulation of several downstream effectors, that include: Raf/Mek/Erk, PI3K/Akt, RalGDS/p38MAPK, and Rac/Rho, and thereby influences tumorigenesis, the invasive behaviors of tumor cell, and resistance to therapy. There is growing evidence exploring the use of drugs that target these pathways in the treatment of CRC. Cetuximab has been approved for CRC patients without a KRAS mutation, or for EGFR-expressing metastatic CRC, although some of the patients have a mutation of KRAS and NRAS. This review summarizes the recent knowledge about the therapeutic potential of targeting RAS with particular emphasis on recent preclinical and clinical studies in treatment of CRC.

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